A blood sample is used for, for example, diagnosis of the state of a subject, judgment for selection of the optimal treatment for disease and the like. However, in some cases, the blood sample which sufficiently reflects the state and disease of a subject cannot be obtained depending on the blood-sampling position. In this case, diagnosis of the state of a subject and judgment for selection of the optimal treatment for disease cannot be accurately carried out.
As a disease for which judgment of the state of the disease or judgment for selection of a treatment method is carried out by using a blood sample, there have been known, for instance, aldosteronism. Aldosteronism is disease which causes hypersecretion of an aldosterone in the suprarenal cortex itself. Aldosteronism is classified roughly into idiopathic hyperaldosteronism and glucocorticoid-remediable hyperaldosteronism which are caused by hyperplasia, and aldosterone-producing adenoma which is caused by adenoma. A treatment method based on drug dosing has been adopted for aldosteronism caused by hyperplasia. In addition, a treatment method based on surgical extirpation has been adopted for aldosterone-producing adenoma.
When a treatment method is selected in accordance with the pattern of disease of the aldosteronism, an adrenal vein sampling test has been conducted (see, for instance, non-patent document 1, non-patent document 2 and the like). In the adrenal vein sampling test, a catheter is inserted into right and left suprarenal veins, about 5 mL of a blood sample is collected, and thereafter the amount of an aldosterone in the blood sample is determined.
However, in the adrenal vein sampling test, since the inside diameter of the suprarenal vein into which a catheter is inserted and the diameter of catheter used is small, blood sampling might be difficult. Moreover, bloods derived from various veins are flown into the suprarenal vein. Therefore, the aldosterone contained in the blood sample obtained by blood sampling might be diluted with the bloods. In this case, the adrenal vein sampling test might not be able to be accurately conducted.
The aptitude of the blood sample used for the adrenal vein sampling test is evaluated on the basis of cortisol concentration in the blood sample. Since a large-scale device is usually necessary for the determination of cortisol concentration, the cortisol concentration could not be easily determined on the surgical site and the like. Therefore, in general, since it is necessary to perform the determination of cortisol concentration in an external institution such as a test agency or a test post, a long term of around several days to one week is required for obtaining the result of the determination.
On the other hand, a substance to be tested, which is contained in a test sample has been detected by an immunochromatography and the like. In the immunochromatography, a liquid dispersion of labeled antibodies obtained by immobilizing antibodies onto the metallic microparticle has been used (see, for instance, patent document 1 and the like).    Patent document 1: Japanese Unexamined Patent Publication No. 2007-169209    Non-patent document 1: Masao Omura, “Diagnosis of specific subtype of primary aldosteronism—signification of adrenal vein sampling”, Saishin Igaku (Current medicine), Saishin Igaku company, 2004, Vol. 59, No. 10, p. 2286-2291    Non-patent document 2: Giulio Mengozzi and other 7 authors, “Rapid Cortisol Assay during Adrenal Vein Sampling in Patients with Primary Aldosteronism”, Clinical Chemistry, November, 2007, Vol. 53, No. 11, p. 1968-1971